I have tried using a board that contains an MCP23017 chip. It seems to work fine in verification tests on a Raspberry Pi 4 (test SW that came with the board).
There are a few things that I don't understand about the suggested settings:
1. Why is 'pin' set to a value of 9? A value of 'I2C' seems to make more sense.
2. When I add the line described in the hardware setting, I expected to get 16 more programmable 'zones' (relays) in the WateringPlan, whereas I get only one, called 'expPIN01'. The home page shows the same thing.
3. When I connect the hardware to the I2C pins, set the address, GND, VCC and one interrupt pin to GND, the Pi does not seem to send any I2C commands.
4. I expected to find a 'canned' setting for the 'expansion board' to be in the drop-down list at the top of the HardwareSetting page, but I don't see it in the list. If it were there, I expect that it would work for my board as well and might have solved my problem.
I fear that I don't understand somthing very basic. Can I get some advice from the Forum?
Images of the screens are below and the HardwareSettings as a pdf file.
Peter Dewdney
Good, I just updated the documentation after I received your comment so probably it was not your fault when you read it the first time 😁. Anyway thanks to your feedback now things are more clear.
After that hint, things indeed began to work. In fact, if I had read the material very carefully, I might have got it right the first time.
Hello,
Each row in the Hardwaresetting corresponds to one GPIO PIN in the MCP23017.
So the PIN field is necessary to select the PIN on the MCP (1-16).
For this reason, it is needed to add 16 lines.
There is not preset setting in the dropdown menu, the operation should be manually made. I know it is tedious, but it is safer in this way. I may add an example in the preset menu to show how it works (this could be actually a good idea).
Let me know if things start to work.
Cheers,
Angelo